Thus, in a main application, but not exclusively, the invention relates to the electrical system on board planes. In such a system, an “electrical power centre” function is conventionally integrated into a technical cargo compartment of the plane so as to manage and distribute electrical power for all consumers. Such management is structured depending on the different operating modes being predefined according to the flight phases and conditions, in particular depending on predetermined failure cases.
Owing to the present tendency to the “all-electrical” on board planes, such electrical system becomes the main system in terms of on-board distribution power for technical and also commercial reasons.
In such conditions, the component size in the electrical system increases substantially and the installation becomes more complex, in particular the implementing means for the electrical power centre function.
The integration of the “electrical power centre” function has thus turned out to be problematic due to the complexity thereof and to the new requirements dictated by safety (for instance, doubling the voltage) as well as to the environmental structures in a composite material based on carbon fibers. The cargo compartment area dedicated to the electrical power centre function is now saturated in terms of congestion, in particular with the number of interconnecting cables between electrical boxes. The maintenance of such area may become delicate.
In general, for practical reasons, the “electrical power centre” function is divided into two independent assemblies, except obviously for the power centre-to-power centre or inter-power centre interconnections arranged “on the left side” and “on the right side” in the dedicated area.
Each of such assemblies comprises a main box, being conventionally designated by “electrical power centre”, and a set of satellite boxes also referred to as “power boxes”. For practical reasons such as congestion, mass, high heat dissipation, problematic electrical connections, and electromagnetic disturbances, such power boxes are not integrated into the main box.
The complexity of the overall installation, resulting from the “all-electrical” evolution mentioned hereinabove, then results in an increasing number of satellite boxes connected to the main box depending on the structure thereof.
In general, each main box can be structured into several main areas: so-called “normal” areas and one emergency area, each area being itself divided into places with different voltages: alternating current and direct current areas. All those areas stay totally independent.
Relating to the satellite boxes, they are formed with equipment dedicated to the power supply of the areas of the main boxes, each satellite box being associated with a determined area. Such equipment using large section electrical connections consist in general in:                autotransformer units (in short ATU) for transforming alternating voltages, each ATU unit having a high mass, typically 30 kg;        transformer-rectifier units (in short TRU) for rectifying alternating current into direct current, each TRU unit having also a high mass, typically about 25 kg;        static undulators for converting direct current into alternating current, with also a typical mass of about 15 to 20 kg; and        batteries of about 50 kg per unit.        
Such conventional architecture suffers from major disadvantages, in particular:                the immobilization of a high volume in the cargo compartment;        over-lengths of connecting cables involving mass loss and a problematic line drop for direct current;        some complexity for wiring and overall integration of the cables;        a reduced access to heavy equipment involving a difficult maintenance, requiring two operators for some equipment;        a specific venting circuit being complex, bulky and expensive due to congestion;        a decreased integrity and thus a reduced reliability for the electrical power centre function due to the fact that such function is burst out and the connecting cables are vulnerable; and        a bad mechanical behaviour, in particular with respect to severe vibrations, of the equipment holding assemblies, such assemblies being sometimes able to be “aerial”, i.e. on a cantilever frame being far from the fuselage; the problem results from the integration from the cubic shape (the equipment) to a wholly curved shape (the lower fuselage boat hull).        